Recently, electronic devices arranges electronic components by high density and increased in amount of heat generated along with their reduction in size and improvement in performance. In particular, in mobile phones, since Apr. 1, 2006, broadcasting services for portable electronic devices have formally started in Japan by the IDSB-T (Integrated service Digital Broadcasting-Terrestrial). It is anticipated that electronic devices mounting TV tuners will increase from now on.
However, TV tuner modules generate a considerable amount of heat during operation. In order to mount electronic components generating heat in this way in small cases such as mobile phones and other portable electronic devices, sufficient countermeasures against heat are necessary.
Conventionally, the following measures have been used to dissipate the heat of electronic components in electronic devices.
There were structures providing a fan structure in a case to cool electronic components generating a large amount of heat or attaching a radiator made of metal. However, in portable devices, use of these structures was difficult due to the problem of space.
Further, there was a structure forming a case of an electronic device by aluminum etc. having a high heat conductivity to improve the heat dissipation. This structure was possible, but had the disadvantage that the effect was low compared with the cost involved.
Other than these, as techniques for dissipating heat from electronic components generating high heat in electronic devices, there are, for example, the techniques disclosed in Patent Documents 1 to 3.    Patent Document 1: Japanese Patent Publication (A) No. 7-221823    Patent Document 2: Japanese Patent Publication (A) No. 2005-244493    Patent Document 3: Japanese Patent Publication (A) No. 2005-534197
Patent Document 1 discloses the technique of mounting an electronic component generating heat in the half of the case of a flip-open type mobile phone not having a receiver so as to suppress transfer of heat to the ear of the user.
Patent Document 2 discloses the technique of making a heat dissipation plate directly abut against an electronic component generating heat to allow heat to escape to the outside.
Patent Document 3 discloses the technique of bonding a special metal foil to a back of a substrate in order to make heat disperse to the back side of a substrate mounting an electronic component generating heat.